Sustainable lignin-derived heteroatom-doped defective carbon cathodes toward superior zinc-air rechargeable batteries

Developing an efficient bifunctional electrocatalyst in the oxygen reduction and evaluation reactions (ORR/OER) remains a major challenge for practical applications of zinc-air rechargeable batteries (ZABs). Herein, we designed a simple approach for fabricating heteroatom-doped (N and P) porous carbon materials using a controlled lignin-supermolecule aggregate that uniformly distributes lignin macromolecules in Lewis acid-base supermolecules. The obtained lignin derived N, P doped carbon (LNPC) with topological defects was prepared by direct pyrolyzing lignin-supermolecule aggregate at high carbonization temperatures. LNPC-1000 exhibited an excellent ORR activity with a high kinetics current density of 25.17 mA cm −2 at 0.85 V, and a superior bifunctional performance (ORR/OER) of a lower ∆E value of 0.87 V, surpassing the benchmark commercial Pt/C electrocatalysts. Besides, a rechargeable zinc-air battery using LNPC-1000 catalyst as the cathodes possesses a high specific capacity of 784.6 mAh g −1 and power density of 143.5 mW cm −2 along with an excellent charge-discharge stability (cumulative 1200 h). Density functional theory (DFT) indicates that heteroatom-doped (N and P) porous carbon with topological defects enhances the bifunctional catalytic effectiveness and can be utilized for practical ZAB applications.